Refactor & optimize utils

- Replaced `copy_level` parameter with more flexible `postprocess`
  callable (defaults to `postprocess_copy_mutables`). Now supports None
  (no copy), shallow copy, deep copy, or custom post-processing.
- Removed deprecated `cachedmethod` decorator (use cached(...,
  cache=lambda self: self._cache) instead).
- `CacheInfo` namedtuple no longer includes the `memory` field.
- Default cache changed from `FIFOCache` to `LRUCache`.
- Fixed incorrect `is_method` handling.
- Improved per-key lock management: now uses a plain `dict` instead of
  `defaultdict`, and removes the lock when no waiters remain (better
  memory behavior under high contention).
- Improved key makers (`make_key`, `make_hash_key`, `make_typed_key`)

Author: awolverp

cachebox/__init__.py

@@ -9,5 +9,18 @@
 from ._core import __version__ as __version__
 from ._core import _small_offset_feature as _small_offset_feature
 
-# utils
+# Utils
 from .utils import Frozen as Frozen
+from .utils import cached as cached
+from .utils import is_cached as is_cached
+
+# Key maker functions
+from .utils import make_hash_key as make_hash_key
+from .utils import make_key as make_key
+from .utils import make_typed_key as make_typed_key
+
+# Postprocess functions
+from .utils import postprocess_copy as postprocess_copy
+from .utils import postprocess_copy_mutables as postprocess_copy_mutables
+from .utils import postprocess_deepcopy as postprocess_deepcopy
+from .utils import postprocess_deepcopy_mutables as postprocess_deepcopy_mutables